He is right that the Spruce Goose is made mostly of laminated birch. I happened to see the plane just two weeks ago. I was visiting my grandparents in McMinnville Oregon home to the Evergreen Aviation Museum which currently houses the Spruce Goose. It is an absolutely humongous plane. The tailspan is that of most commercial jets' wingspan. You can get more info on the plane at the link below,

Simon

: I was going by what I remember from my local museum, The Washington State
: History Museum. They have a display about warplanes made of spruce,
: complete with bullet holes. I thought they mentioned the Spruce Goose,
: I'll check next time I go there.